Long-term potentiation (LTP) is a long-lasting enhancement in signal transmission between two neurons that results from stimulating the neurons synchronously. LTP is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. At a cellular level, LTP enhances synaptic transmission as it improves the ability of two neurons, one presynaptic and the other postsynaptic, to communicate with one another across a synapse. Thus, LTP is a persistent increase in synaptic strength following high-frequency stimulation of a chemical synapse.
As learning and memory, both memory acquisition and memory recall, are thought to be encoded by modification of synaptic strength, LTP is widely considered one of the major cellular mechanisms that underlies those functions. LTP may account for many types of learning, from the relatively simple classical conditioning present in all animals, to the more complex, higher-level cognition observed in humans.
The hippocampus is a major component of the brain of humans, belonging to the limbic system. The hippocampus plays significant roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. As different neuronal cell types are neatly organized into layers in the hippocampus, it has frequently been used as the model system for studying neurophysiology, and in particular, for studying LTP.
Various diseases and conditions affect hippocampus and its related functions, such as cognition, including both learning and memory. For example, stress, and stress-related hormones released in response to stress, affect the hippocampus in at least three ways: first, by reducing the excitability of some hippocampal neurons; second, by inhibiting the genesis of new neurons in the dentate gyrus; and third, by causing atrophy of dendrites in pyramidal cells of the CA3 region. There has now been evidence that humans that experience stress can affect hippocampal function, including learning and memory that may persist throughout life.
Accordingly, it would be desirable to provide nutritional compositions that provide individual components that can induce higher long-term potentiation in hippocampal neuronal synapsis, thereby enhancing cognitive performance, and particularly, memory acquisition, memory retention, and memory recall that may contribute to the learning and memory processes. It would also be beneficial if the nutritional compositions could be utilized early in life to maximize benefits throughout life.